Patent GB-883216-A (GB)
Title: Apparatus for lifting railway tracks
IPC: E01B33/02
Filed: 1959-05-20
Abstract: 883,216. Apparatus for lifting railway tracks. MATERIEL INDUSTRIEL S.A., and CONSTRUCTIONS MECANIQUES S.A. RENENS. May 20, 1959 [May 23, 1958] No. 17142/59. Class 104 (2). Railway tracks are raised and lowered to a set predetermined level by a vehicle mounted on a track 1, la and provided with hooks 16, 16a which engage the track 1, 1a and are raised or lowered by hydraulic jacks 10, 10a mounted on the vehicle and acting against the ballast 3. The operation of the jacks 10, 10a being controlled by hydraulic distributers controlled by sensing elements 8, 8a mounted on the vehicle and raised or lowered with the tracks to engage stops 28, 28a to stop movement of the track when at the required position. In the arrangement shown in Fig. 1, the machine comprises a supply motor-pump 6 and an oil tank 7, containing the control members, mounted on a chassis 5 running on flanged wheels 4. Two stops 28, 28a, Fig. 3, secured to an auxiliary device which rests on the ballasts, are arranged to project above two fingers 8, 8a (Fig. 3) in a plane x halfway between the wheels 4. The lifting device carries two hydraulic jacks 10, 10a on a transverse beam comprising two U- shaped members 12, 13 to which are pivoted at 14, 14a two hook-shaped levers 16, 16a pivotally connected to an hydraulic jack 19. Two wheels 20 of the lifting device are mounted on two levers 21 pivotally mounted at 22 on the beam 13 against the upper part of which abuts an adjusting screw 23. The drawbar 24 is adjustably hinged at 25 to the chassis 5 and pivotally mounted at 26 on the beam 12 against the upper part of which abuts an adjusting screw 27. The apparatus operates in the following manner. A push-button 9 is actuated to effect the expansion of the jack 19 to move the hook levers 16, 16a into engagement with the underside of the heads of the rails 1, la and the jacks 10, 10a are then operated to press their bases 11, 11a on to the ballast to lift the rails 1, 1a until the fingers 8 or 8a or both contact the stops 28 or 28a or both to stop the jacks 10, 10a operating and the rail is then lifted to the required height. The three jacks 10, 10a and 19 are returned to their inoperative positions on release of pushbutton 9. The apparatus enclosed in the tank 7 for operating the jacks 10, 10a and 19 is shown in Fig. 3 and operates as follows. The push-button 9 in the position shown, is in its inoperative position, so that slide valve 50 connects conduit 42 with a discharge opening 56 to relieve pressure in a pump 41 and chamber 33 of the jack 19. Chamber 34 of the jack 19 and chambers 32, 32a of the jacks 10, 10a are subjected to the pressure of the pumps 40 through conduits 39, 37 and 35 since a check valve 38 only provides a negligible resistance. A small amount of fluid flows at very low rate, due to apertured diaphragms 47, 47a, through conduits 46, 46a to chambers 45, 45a of distributers 43, 43a connected by conduits 49, 49a to discharge openings 59, 59a of distributers 48, 48a so that the slide valves 51 and 51a, biased by springs 54, 54a, connect conduits 44, 44a to the discharge openings 58, 58a to relieve pressure in the chambers 31, 31a of jacks 10, 10a and in conduits 75, 75a. The pressure in conduit 72 and chamber 70 is at zero because an apertured diaphragm 71 and piston 68 effect a minimum compression of a spring 65 determined by an adjustment member 67. The three jacks 10, 10a and 19 are then held in the inoperative position by the pump 40. When the pushbutton 9 is depressed the slide valve 50 connects the conduit 35 to an outlet 57 to discharge chambers 32, 32a and 34 while conduit 37 communicates with conduit 42 which is cut off from opening 56. The pressure, due to pumps 40, 41, rises progressively in conduit 42 and chamber 33 to actuate the jack 19. Simultaneously, levers 60, 60a are pivoted away from collars 63, 63a to allow slide valves 52, 52a to be moved upwards by springs 55, 55a to close conduits 49, 49a which results in an increase in pressure in chambers 45, 45a fed through conduits 46, 46a from pump 40. The slide valves 51, 51a are now moved against the springs 54, 54a to connect conduit 42 with the conduits 44, 44a, which are cut off from outlets 58, 58a, to subject chambers 31, 31a to an increasing pressure from pumps 40, 41 to operate the jacks 10, 10a and lift the rails 1, la. At the same time pressure increases in the conduits 75, 75a and fluid flows through check valves 74, 74a and through an apertured diaphragm 73 into chamber 70 and through the apertured diaphragm 71 to cause a slight increase of pressure in the chamber 70, but not sufficient to move the piston 68 against the spring 65. When the pressure in the conduit 42 reaches a maximum pressure exerted by the pump 40, the check valve 38 closes and pressure in conduit 44 continues to increase due to the effect of the high pressure pump 41 and the piston 68 is finally caused to move to compress the spring 65 to keep the valve 64 closed. When the pressure in conduit 42 is sufficient the rails 1, 1a are lifted until the finger 8, for instance, contacts the stop 28 to press the slide valve 52 into the body of the distributer 48 to place conduit 49 slightly into communication with the outlet 59 to decrease the pressure in the chamber 45. The slide valve 51 now tends to cut off conduit 44 from conduit 42 and to place the latter in communication with outlet 58, thus arresting the lifting movement of the jack 10 independently of the jack 10a which is only arrested in a similar manner when finger 8a abuts the stop 28a. In a modification, Fig. 5 (not shown), the distributer 43a and 48a are combined in a single casing and the pressure from the distributer acts on an inclined face to reproduce the vertical movement of the finger in relation to the casing. In a further modification, Fig. 6 (not shown), the conduit 75 is connected to an hydraulic relay which, through a distributer, effects the closing of spaces of a conventional tamping device.